Russia and China on Monday vetoed a UN Security Council resolution that would have provided respite to Syrians as desperately-needed humanitarian aid flows into the battled city of Aleppo.

The plan to hold up a seven-day cessation of hostilities fell by the wayside after the two of the five permanent members of the Council, as well as a as a non-permanent member, Venezuela, voted to shoot down the bill. The other permanent members include France, U.K. and the U.S.

The resolution needed 9 out of the 15 Council votes and the non-rejection of all five permanent members.

It marks the fifth time Russia and China jointly blocked Security Council action on Syria, and the sixth for Russia on its own.

"Russia has held to ransom lives of hundreds of thousands of innocent men, women & children enduring hell in #Aleppo," U.K.'s ambassador to the UN, Matthew Rycroft, wrote on Twitter.

In a speech before the Council, Rycroft dismissed Russia's claim of helping the Syrian regime "fight terrorists" as "pure fantasy".

U.S. deputy ambassador to the UN, Michele Sison, blamed Moscow for the international community's failure to bring about an end to violence in Syria "because Russia is more concerned with preserving its military gains”.

French permanent representative to the UN, Francois Delattre said in the absence of any consensus on a political resolution, Syria will remain "divided, beset by constant fighting, a bastion of terrorism".

A similar seven-day truce in September ended catastrophically after a UN aid convoy was bombed before reaching Aleppo to deliver aid.

Aleppo, pre-war Syria's second largest city, is left in utter ruin, with hundreds of thousands of civilian residents trapped in the crossfire between indiscriminate Russian and Syrian airstrikes and Daesh terrorism.